This is from Palembang, year 1203 H (1789 AD). The difficulty lies in its being entirely "retrograde (mirror image)". The term may be incorrect. A photo of the coin is in Palembang Coins, 2015, by Frank S. Robinson, p10 #9.31. On a scale of 1 to 10, it is rated R-4. For this date there are 50 varieties pictured.